Furnace-top distributor for shaft furnaces

ABSTRACT

To form a top distributor for a shaft furnace without the use of moving parts, a gas inlet port and a gas outlet port are formed in the opposite sides of the upper portion of the shaft so that a flow of gas from the inlet port to the outlet port traverses the shaft perpendicularly to the gas rising in the shaft. A thrust generator supplies gas to the inlet port and a suction device withdraws gas from the outlet port. The inlet and outlet ports each have a funnel-shaped configuration with the wider end connected to the shaft and the narrower end extending outwardly from the shaft. Further, the cross-sectional area of the outlet port at its connection to the shaft is larger than the crosssectional area of the inlet port at its connection to the shaft.

[ 51 Oct. 22, 19774 United States Patent [191 Burger [54] FURNACE-TOP DISTRIBUTOR FOR SHAFT 3,702,242 ll/1972 Fernandes....................... 266/27 X FURNACES [75] Inventor:

H B S h ffh Primary Examiner-Gerald A. Dost x z gfi c a ausen gttggiy, Agent, or Firm-Toren, McGeady and [73] Assignee: Georg Fischer Aktiengesellschaft,

Schaffhausen, Switzerland Aug. 1, 1973 [57] ABSTRACT To form a top distributor for a shaft furnace without the use of moving parts, a gas inlet port and a gas out- 22 Filed:

[2]] Appl. No.: 384,411

let port are formed in the opposite sides of the upper portion of the shaft so that a flow of gas from the inlet [30] Foreign Application Priority Data Aug. 11, 1972 Switzerland.......................

port to the outlet port traverses the shaft perpendicularly to the gas rising in the shaft. A thrust generator supplies gas to the inlet port and a suction device withdraws gas from the outlet port. The inlet and out- 70 21 I b 7 2 F U St Uh .ll. 21 55 [i let ports each have a funnel-shaped configuration with the wider end connected to the shaft and the narrower end extending outwardly from the shaft. Further, the

[58] Field of Search........ 2l4/35 R, 36, 37; 266/27,

cross-sectional area of the outlet port at its connection [56] References cued to the shaft is larger than the cross-sectional area of UNITED STATES PATENTS the inlet port at its connection to the shaft.

2,729,301 1/1956 266/31 3,077,274 2/1963 266/27 x 6 Draw; F'gures PATENTED um 22 19M MEI 20$ 3 Fig; 3

FURNACE-TOP DISTRIBUTOR FOR SHAFT FURNACES SUMMARY OF THE INVENTION The present invention is directed to a top distributor for shaft furnaces, especially cupola furnaces, having a charging aperture in the upper portion of the furnace and, more particularly, it is directed to the arrangement of a gas inlet port and gas outlet port for directing a flow of gas across the shaft transversely of the flow of gases within the shaft.

Various top distributors have been used in cupola furnaces to keep the charging opening closed even during charging operations.

In German Patent No. 1,250,600 a cupola furnace is disclosed with a charging bucket positioned in the charging opening so that it forms a closure for the opening. A two-part locking device is incorporated into the throat of the furnace and is designed as a slide which can be actuated following the placement of the charging bucket. When the two-part locking device is opened, the bottom lock of the charging bucket is opened so that the charge flows into the cupola furnace. After the actuation of the bottom lock on the bucket, the two-part locking device, designed as a slide incorporated into the throat of the cupola furnace is closed. This arrangement has been used in a variety of embodiments.

As is well known in the art, when a cupola furnace is placed in. operation and also during shut-down operations and during operation without a charge, extraordinarily hot flue gases are generated which contain a high percentage of dust. Due to the great temperature differences involved in such operations, it is practically impossible to avoid distortions in the various charging components and careful servicing is required to assure that they continue to operate.

It is the primary object of the present invention to provide a top distributor which does away with the use of movable components and provides a practically hermetic seal between the charging opening and the throat of the shaft furnace, even during charging operations. Furthermore, it is possible to utilize the arrangement of the present invention in existing shaft furnace installations.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWING In the drawing:

FIG. 1 is a schematic representation of the upper part of a cupola furnace illustrated in a vertical crosssectional view and embodying the present invention;

FIG. 2 is a transverse cross-sectional view taken along the line [-1 of FIG. 1;

FIG. 3 is a view, similar to FIG. 1, of the schematic arrangement of the upper part of the cupola furnace displaying another embodiment of the present invention;

FIG. 4 is a schematic representation of the upper part of a cupola furnace in a cross-sectional view similarto FIG. 1 and illustrating the arrangement of the exhaust gas lines from the furnace in combination with the arrangement of the present invention;

FIG. 5 is a view, similar to FIG. 4, showing another arrangement of the present invention connected to the exhaust gas lines; and

FIG. 6 is another representation, similar to FIG. 4, showing still another arrangement of the present inventron.

DETAILED DESCRIPTION OF THE INVENTION In FIG. 1 the upper part of a cupola furnace 16 is shown schematically with a shaft portion 1 projecting upwardly into the furnace throat 10. The shaft portion 1 has an upper frusto-conical portion and a lower substantially cylindrical portion extending downwardly into the furnace shaft 21. The shaft portion 1 forms a space for receiving the charge as it passes downwardly into the furnace shaft. The shaft portion 1 is spaced radially inwardly from the furnace throat 10 so that an annular space 15 is formed between the two into which flue gasespass prior to flowing outwardly through the flue gas line 12.

Above the shaft portion 1, a charging aperture 2 is formed in throat wall 3. Between the .shaft portion 1 and the charging aperture 2, a slot-shaped gas supply port 6 extends around a portion of the circumference of the throat wall. The supply or inlet port 6 is funnelshaped with its larger end connected to the throat wall and its smaller end projecting outwardly from it. An exhaust or outlet port 9 is formed in the throat wall on the opposite side from the inlet port 6 and is also funnelshaped with its larger end connected to the throat wall and its smaller end projecting outwardly from it. As can be appreciated from FIGS. 1, 2 and 3, it can be seen that the cross-sectional area of the inlet port 6, at its connection to the throat wall 3, is smaller than the cross-sectional area of the outlet port at the similar location. This difference in cross-sectional areas aids in the functioning of the invention. The combination of the inlet and outlet ports defines a transverse crosssectional area 14 in the throat which is larger than the cross-sectional areas of the throat immediately above and below the area 14, note FIG. 2. Further, in accordance with the present invention, it is possible to arrange a plurality of inlet and outlet ports 6, 9 at different levels in the furnace throat 10 with one outlet port 9 or a plurality of outlet ports 9' associated with each of the inlet ports 6.. Furthermore, it is also possible to vary the direction of the oppositely disposed opening axes.

In FIG. 1, a supply conduit 5 extends between a thrust generator 4 and the inlet port 6. The thrust generator 4 is, for example, a variable output fan which is connected to the flue gas line 12 connected to the annular space 15 at the upper end of the furnace shaft. As shown in FIG. 4, the thrust generator can also be connected into the gas line from the furnace at a point where unpurified gas is being conveyed between a gas processing chamber 28 and a gas cooler and filter 29. Alternatively, the thrust generator can be connected to the exhaust gas line downstream from the gas filter where the line conveys purified gas, note FIG. 5. In still another alternative, such as when the furnace operates with a lean carbon monoxide content or is free of carbon monoxide, the thrust generator 4 can be connected to a line 22 for drawing in ambient air for supply to the inlet port 6, note FIG. 6.

An exhaust conduit 8 connects the outlet port 9 to a suction device 7, such as a variable output fan, and the suction device is connected, in turn, to the flue gas exhaust line 12. Depending on the type of cupola furnace operation involved, a dust separator 13, shown in dashed lines, and/or a safety burner 20 is connected to the exhaust conduit 8 upstream from the suction device.

In FIG. 3 the upper part of a cupola furnace 18 is shown in a schematic manner and, as distinguished from FIG. 1, it does not contain a flue gas exhaust outlet located below the charging aperture. For charging the furnace 18, a charge aperture 26 of conventional design is formed in the furnace wall 27. In the furnace wall 27, closely spaced below the charge aperture or opening 26, a slot-shaped gas supply inlet port 6 is connected to and extends about a portion of the circumferential periphery of the wall. The inlet port 6 is funnelshaped with its larger end connected to the furnace wall and its smaller end disposed outwardly from the wall. Situated diametrically opposite the inlet port is a slot-shaped gas outlet port 9 also having a funnelshaped configuration with its larger end connected to the circumferential periphery of the wall and its smaller end located outwardly from the wall. As with the arrangement of the inlet and outlet ports in FIG. 1, the cross-sectional area of the inlet port 6 is smaller than that of the outlet port 9 in accordance with the functioning of the arrangement. The walls of the ports 6, 9 form a throat cross-section similar to that shown in FIG. 2, which is larger than the cross-sectional area within the furnace immediately above and below the throat cross-section formed by the ports. As in the arrangement shown in FIG. 1, it is possible to arrange a plurality of ports 6 and 9 at'different levels in the furnace throat 10. With regard to the exhaust ports, a single exhaust port 9 or multiple exhaust ports 9', as shown in dashed lines in FIG. 2, may be arranged diametrically opposite the supply port 6. Further, the arrangement of the axes of the inlet and outlet ports can be varied as long as a transverse flow across the furnace shaft is provided.

Outwardly from the cupola furnace 18, a thrust generator 4 is connected over a supply duct to the inlet port 6. The thrust generator 4 may, for instance, be a variable output fan positioned within a intake line 22 for drawing in ambient air. An exhaust conduit 8 is connected to the outlet port 9 at one end and its other end is connected to a dust separator 13 equipped with a suction device 7'. Preferably, the suction device has a variable output. Further, in accordance with the type of operation used for the cupola furnace, a safety burner and/or a gas processing chamber 19, shown in dashed lines, can be connected into the exhaust conduit 8. The gas processing chamber 19 may be a gas tank or a combustion chamber.

It is possible to use the top distributor described above as an independent device 25, note the full line showing in FIG. 1 and the phantom showing in FIG. 3, as well as being directly incorporated into the upper portion of shaft furnaces known in the art so that it can be used with known charging devices. Further, it is possible to use the top distributor in combination with existing suction devices for discharging any residual gases the furnace. Essentially the present invention operates in the following manner: by means of the thrust generator 4 gas is drawn by suction out of the gas exhaust line 12 or ambient air is drawn in through the line 22, the gas is compressed and passed to the inlet port 6 through the line 5 and the degree of purity of the gas used is not important. The gas from the inlet port 6 is directed transversely across the shaft furnace perpendicularly of the upward flow of gas through the furnace and is withdrawn through the outlet port 9 into the exhaust conduit 8 by means of the suction device 7. By adjusting the gas supply to the inlet port and, accordingly, the gas exhausted through the outlet port, it is possible to create a favorable cross flow adapted to variable furnace operations, so that the flue gases rising upwardly through the shaft furnace are exhausted. Accordingly, the transverse gas flow 11, as shown in FIGS. 1 and 3, forms a pneumatically operated top distributor.

By virtue of the present invention, it is possible to provide a top distributor which does not require any movable components and which, even during charging operations, can guarantee a practically hermetically sealed furnace throat which does not impede the charging operation. Existing cupola furnaces can be outfitted with the device according to the present invention and existing charging devices arranged either at the circumference or on the cover of the furnace throat can be used with the device.

While specific embodiments of the invention have been shown and described in detail to illustrate the application of the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

What is claimed is:

1. Top distributor for a shaft furnace, in particular a cupola furnace, comprising furnace walls forming an upwardly extending shaft having a lower portion arranged to contain a charge and an upper portion located above the charge, said upper portion forming a charging aperture, wherein the improvement comprises a gas inlet port formed in one side of said upper portion, a gas outlet port formed in said upper portion on the opposite side thereof from said inlet port and in alignment with said inlet port, a thrust generator located exteriorly of said shaft, a duct connected to said generator and said inlet port for supplying a flow of gas to said inlet port, a suction device located exteriorly of said shaft, a pipe connected between said outlet port and said suction device so that the flow of gas directed into said shaft from said inlet port traverses said shaft perpendicularly to the gas rising in the shaft and flows outwardly through said outlet port, and the crosssectional area of said inlet port at its connection to said shaft is smaller than the cross-sectional area of said outlet port at its connection to said shaft.

2. Top distributor for a shaft furnace, as set forth in claim 1, wherein an exhaust conduit for flue gas is connected to said shaft below the connections of said inlet and outlet ports and said thrust generator is connected to said exhaust conduit for withdrawing flue gas from said exhaust conduit, compressing the flue gas and delivering it to said inlet port.

3. Top distributor for a shaft furnace, as set forth in claim 2, wherein a gas processing chamber is positioned in said exhaust gas conduit upstream from the connection of said thrust generator to said exhaust conduit so that unpurified gases flow to said thrust generator from said exhaust gas conduit.

4. Top distributor for a shaft furnace, as set forth in claim 2, wherein a gas cooler and filter are located in said exhaust gas conduit upstream from the connection of said thrust generator to said exhaust gas conduit so that purified gases flow to said thrust generator from said exhaust gas conduit.

' 5. Top distributor for a shaft furnace, as set forth in claim 2, wherein an inlet line is connected at one end to said thrust generator and at its other end is open to the atmosphere for supplying ambient air to said inlet port.

6. Top distributor for a shaft furnace, as set forth in claim 2, wherein an exhaust conduit for flue gas is connected to said shaft below the connection of said outlet port and said suction device is connected to said exhaust conduit for directing the gas received from said outlet port into said exhaust conduit.

7. Top distributor for a shaft furnace, as set forth in claim 1, wherein a dust separator is connected to said pipe connecting said outlet port to said suction device.

8. Top distributor for a shaft furnace, as set forth in claim 1, wherein a safety burner is connected to said pipe connecting said outlet port to said suction device.

9. Top distributor for a shaft furnace, in particular a cupola furnace, comprising furnace walls forming an upwardly extending shaft having a lower portion arranged .to contain a charge and an upper portion located above the charge, said upper portion forming a charging aperture, wherein the improvement comprises a gas inlet port formed in one side of said upper portion, a gas outlet port formed in said upper portion on the opposite side thereof from said inlet port and in alignment with said inlet port, a thrust generator located exteriorly of said shaft, a duct connected to said generator and said inlet port for supplying a flow of gas to said inlet port, a suction device located exteriorly of said shaft, a pipe connected between said outlet port and said suction device so that the flow of gas directed into said shaft fromsaid inlet port traverses said shaft perpendicularly to the gas rising in the shaft and flows outwardly through said outlet port, and said inlet port and said outlet port each project outwardly from said shaft and each has a funnel-shaped configuration with the wider portion thereof connected to said shaft and the narrower portion projecting outwardly from said shaft.

10. Top distributor for a shaft furnace, as set forth in claim 9, wherein the funnel-shaped said inlet and outlet ports each have a slot-like configuration at its point of connection to said shaft and the slot-like configuration is elongated in the direction extending transversely of the axial direction of said shaft. 

1. Top distributor for a shaft furnace, in particular a cupola furnace, comprising furnace walls forming an upwardly extending shaft having a lower portion arranged to contain a charge and an upper portion located above the charge, said upper portion forming a charging aperture, wherein the improvement comprises a gas inlet port formed in one side of said upper portion, a gas outlet port formed in said upper portion on the opposite side thereof from said inlet port and in alignment with said inlet port, a thrust generator located exteriorly of said shaft, a duct connected to said generator and said inlet port for supplying a flow of gas to said inlet port, a suction device located exteriorly of said shaft, a pipe connected between said outlet port and said suction device so that the flow of gas directed into said shaft from said inlet port traverses said shaft perpendicularly to the gas rising in the shaft and flows outwardly through said outlet port, and the cross-sectional area of said inlet port at its connection to said shaft is smaller than the cross-sectional area of said outlet port at its connection to said shaft.
 2. Top distributor for a shaft furnace, as set forth in claim 1, wherein an exhaust conduit for flue gas is connected to said shaft below the connections of said inlet and outlet ports and said thrust generator is connected to said exhaust conduit for withdrawing flue gas from said exhaust conduit, compressing the flue gas and delivering it to said inlet port.
 3. Top distributor for a shaft furnace, as set forth in claim 2, wherein a gas processing chamber is positioned in said exhaust gas conduit upstream from the connection of said thrust generator to said exhaust conduit so that unpurified gases flow to said thrust generator from said exhaust gas conduit.
 4. Top distributor for a shaft furnace, as set forth in claim 2, wherein a gas cooler and filter are located in said exhaust gas conduit upstream from the connection of said thrust generator to said exhaust gas conduit so that purified gases flow to said thrust generator from said exhaust gas conduit.
 5. Top distributor for a shaft furnace, as set forth in claim 2, wherein an inlet line is connected at one end to said thrust generator and at its other end is open to the atmosphere for supplying ambient air to said inlet port.
 6. Top distributor for a shaft furnace, as set forth in claim 2, wherein an exhaust conduit for flue gas is connected to said shaft below the connection of said outlet port and said suction device is connected to said exhaust conduit for directing the gas received from said outlet port into said exhaust conduit.
 7. Top distributor for a shaft furnace, as set forth in claim 1, wherein a dust separator is connected to said pipe connecting said outlet port to said suction device.
 8. Top distributor for a shaft furnace, as set forth in claim 1, wherein a safety burner is coNnected to said pipe connecting said outlet port to said suction device.
 9. Top distributor for a shaft furnace, in particular a cupola furnace, comprising furnace walls forming an upwardly extending shaft having a lower portion arranged to contain a charge and an upper portion located above the charge, said upper portion forming a charging aperture, wherein the improvement comprises a gas inlet port formed in one side of said upper portion, a gas outlet port formed in said upper portion on the opposite side thereof from said inlet port and in alignment with said inlet port, a thrust generator located exteriorly of said shaft, a duct connected to said generator and said inlet port for supplying a flow of gas to said inlet port, a suction device located exteriorly of said shaft, a pipe connected between said outlet port and said suction device so that the flow of gas directed into said shaft from said inlet port traverses said shaft perpendicularly to the gas rising in the shaft and flows outwardly through said outlet port, and said inlet port and said outlet port each project outwardly from said shaft and each has a funnel-shaped configuration with the wider portion thereof connected to said shaft and the narrower portion projecting outwardly from said shaft.
 10. Top distributor for a shaft furnace, as set forth in claim 9, wherein the funnel-shaped said inlet and outlet ports each have a slot-like configuration at its point of connection to said shaft and the slot-like configuration is elongated in the direction extending transversely of the axial direction of said shaft. 